The American Philatelic Society
The organization for stamp collectors, located in PA. Being an APS member gives you great benefits, and prestige!

United States Postal Service
Good online exhibits and news on new issues.

The National Postal Museum
The Smithsonian's newest museum, and a great one!

Encyclopedia Smithsonian: Postal History
This page of Smithsonian Online has philatelic-related links from all of the Smithsonian websites.

Philatelic.com and Philatelic.net
The ultimate stamp collecting website (besides ours, of course!).

Linn's Stamp News
The online version of the informative stamp weekly.